The present invention relates to a portable telephone communications system which has particular applicability for use in automobiles, although its use is not necessarily restricted thereto.
Many types of portable telephone communications systems have been developed for assisting car drivers in the portable telephone communications while driving. These portable telephone communications systems generally consist of a repeater unit (main body) which is connected to the portable telephone terminal and a cordless remote receiver unit (earphone) which is connected to the main body of mobile telephone by infra-red rays and put over caller's ears. Such type of portable telephone communications systems are called "hand-free communications system", "hands-free communications system", or "cordless communications system", etc.
Japanese Patent Application HEISEI-09-2734855, for example, discloses an invention of hands-free type communications system which enables caller to off-hook for starting/receiving a call, to on-hook after the communication is over by the operation of the switch installed in the communications device which is put over the caller's ears. However, in this system, as the power to the main body is always supplied from the car battery through cigarette lighter outlet and that of the earphone is always supplied from built-in battery (such as dry battery), both require caller's hand operations for turning off the power switch. Further, it specifies only that the on/off-hook control switch installed in the earphone works to turn on the switch when pressed once and turn off when pressed once again. Based on this, we assume that after the communication is over, the system requires caller not only manual operation on the switch installed over caller's ear but also frequent switch-off operation of the power to the earphone for longer life of the battery. Consequently, caller needs to pay attention all the time to the switching operation of both hook and power switches.
Japanese Patent Journal HEISEI-9-162961 discloses an invention of cordless communications system, utilizing infra-red ray. It describes only the transmitting/receiving action by infra-red ray during communications but not controlling operation for starting and terminating the communications or technical details of devices. In this system, one-way PTT switching system is adopted for the transmission/reception of communication and the simultaneous two-way communications as with normal telephone is not possible. It is used rather in the same way as with transceiver. Accordingly, the transmission/reception switching, manual PTT operation is required. Although there is no details mentioned on the power supply to the transmission/reception circuit unit which is put on the caller, it is assumed that the power is supplied by battery, such as battery cells. Consequently, manual operation of power switch is required for turning off the power switch. To this end, caller must always pay attention to the operation of both PTT and power switches.
Japanese Patent Journal HEISEI-4-249433 discloses an invention of amplifier to set a portable telephone and head set which enables hands-free communications from the amplifier, using infra-red rays. It is explained that the invention enables hands-free communications, utilizing infra-red rays by frequency modulation. The power to amplifier in this invention is supplied from car battery, and it is assumed to be either type of power switching systems which need to be on for initiating a call or left on at all time. Further although there is no mention on the power supply to the head set, it is assumed that the power is supplied always from battery (such as battery cells) and it requires call's manual operation to turn off the power. In this journal, it is only mentioned that the adoption of infra-red ray communications using said frequency modulation enables such a hands-free communications function. It is assumed, consequently, that in this system, the power supply needs to be controlled either with manual switch on the amplifier to turn on or left on at all time without providing any power switches, where the energy-saving is essentially impossible. The power of head-set also needs to be manually switched off. Therefore, caller (driver) is obliged to always pay attention to the power switching operation. Further, with the adoption of frequency modulation method, high-level output noise is generated when no signals are received. However, considering that there is no special measures to take mentioned in the journal, it is assumed that caller cannot avoid hearing the noise. Consequently, it is inevitable for caller to operate the switch of the head-set power to turn off as soon as the communication is over.
Further, Japanese Patent Journal SHOWA-56-152343 discloses cordless amplifier telephone system. It is specified that this telephone system enables to control the communication at a distance by the transmitter unit which is connected to the dial, hook switch and microphone. Based on the specification, the starting of call by dial needs dialling operation while pressing the hook switch installed on the transmitter unit, and it is assumed that complicated one-hand operations is indispensable in this system. If that is the case, as the operation can be easier when it is not cordless, it would be difficult to apply this invention in a car. Besides, as to dialling signals, hook signals and voice signals which are necessarily supplied at the starting of call, it only specifies that dialling signals, on-off hook signals and voice signals generate signals, "after being supplied to the repeater . . . are transmitted . . . transmission media, such as magnetic waves, sound and light".
Japanese Patent Journal HEISEI-7-28749 discloses an invention of adapter to be installed in a car for portable telephone communications in order to enable car driver hand-free communications. By installing this adapter to the portable telephone, the microphone and speaker which are already installed in the adapter can be connected to the input/output terminal of the portable telephone, and the hand-free communications function can be provided. Based on the description that the microphone is a condenser microphone, it is assumed with this adapter that it is not possible for car driver to immediately respond to the received call unless the power is always left on. Further, when installed in a car, the adapter needs at least separate wiring for speaker and microphone in the car. If the wiring is long or incidentally so long as it easily picks up the electrical transmission waves from radio broadcasting station or wireless radio station, a certain current which corresponds with broadcasting from the radio broadcasting station or communications from the wireless radio station is induced by such broadcasting waves or radio communication waves, and, as a result, so called inference may be occurred.
Besides, it is mentioned that car driver can respond to received calls by turning on the communication switch which is installed on the portable telephone itself. Based on this, it is assumed that car driver needs to operate the communication switch, while visually checking the portable telephone or groping for the switch. It is also mentioned that the microphone installed on the adapter can be wireless, which does not specify anything more but "The microphone may be wireless microphone".
With the proliferation of portable telephones, people's usage of portable telephones, while driving a car is increasing. On the other hand, the rapid increase in number of accidents caused by the use of portable telephones while driving a car is becoming a centre of attention of the public. In Japan, the Traffic Bureau of the National Policy Agency reported results of its scientific research to the National Public Safety Commission on Mar. 19, 1998. The report says that one-hand driving makes the wheel operation unsteady and driving unsafe, which may easily lead to accident (source: Asahi Evening of the same day).
The report also says that portable telephone communications systems by which is meant any type of hands-free communications system consisting of main body (transmitter unit) and earphone (remote receiver unit), enabling cordless communications as mentioned above is "considered to be effective, to a certain extent, for preventing car drivers from taking their eyes off the road", however, the time during which caller ("Caller" hereinafter means car driver who is communicating on a portable telephone while driving) is preoccupied with the operation of such portable telephone communications systems for responding to received calls is 1.66 seconds in average. If driving at 40 km/hr, the car advances about 18.4 m in such instance. The report warns of the dangers of about 20 m advance of the car without visual checking of the conditions in front of the driving car, while the driver is taking eyes off the road for just 1 second.
The report further informs that accidents occurring when a car driver receives calls account for 41% of total traffic accidents related to portable telephone operations, and receiving calls became the top reason of traffic accident. At the start of communicating on a portable telephone, accidents can be prevented from occurring by stopping the car at the shoulder of road to do such operations. However, received calls generally involve noisy alarm sounds, etc of portable telephone and urge car drivers to respond to the calls, and they tend to immediately respond risking taking their eyes off the road for an instant.
At this time, as an electricity-saving-conscious car driver tends to keep the power switch of said earphone off, he would need to grope for power switch, turn it on, and then press the communication button on the portable telephone to respond to the received call. In such operation on conventional systems, car drivers tend to press the power switch twice by mistake, and unintentionally terminate unfinished communication or take time to respond to the received call because of the facts that: (1) conventional systems generally use toggle switch for power switch, (2) the position of power switch cannot be found so easily as it is located over car driver's ear, and (3) the car driver tends to forget whether he had turned it off after the communication is over. As a result, the car drivers are too much distracted by minding about the power-switch operation and this may easily cause a traffic accident, which has become a serious social issue.
Conventional systems necessarily require some kind of manual turn-off operation after the communication is over, if power switch of earphone is designed to be pressed once to turn on the power, otherwise the power is left on after it has been turned on. Also for a car driver who is not conscious of electrical saving, there is a disadvantage of frequently required battery changes because batteries could be wasted due to failure of power-off operation as battery of the earphone normally runs out very quickly in a short time.
In the case where the main body of mobile telephone and earphone are connected with infra-red ray communications by the frequency modulation, there is a loud output noise when no signals are received. Consequently, caller needs to turn off the switch as soon as the communication is over or adjust the sound volume. Because of such operations, car drivers tend to be preoccupied increasing the number of traffic accidents in the way as described above.
Further, as the power of the main body of the mobile telephone (especially, of the type that is installed in the car) is normally supplied from car battery through a cigarette lighter outlet, such hands free communications system cannot be used when the car engine is stopped. On the other hand, when the power is supplied from dry batteries built in the system, there is a disadvantage that caller needs to change batteries frequently, as they run out quickly if the power of the main body is left on, which may cause more trouble of maintenance.
For avoiding such occurrences, the caller must diligently turn off the power of main body. However, this causes the problem of increased risk of car drivers taking their eyes off the road, and, further, as they cannot immediately respond to received calls, they tend to lose concentration on driving of the car.
There is thereby a need for a system which addresses these problems.
More particularly there is a need for a portable telephone communications system which is designed to enable the communications on a portable telephone without requiring two-hand operation, to thereby make driving safer. Further, there is a need for a portable phone communications system which enables caller to turn on the power of remote receiver unit for responding to received call by only one press of the power switch button installed in the remote receiver unit (earphone) which is put over caller's ear, and the power to be turned offer automatically so that no particular power switching operation is required after the communication is over.